Zirconia based ceramic material

摘要

A zirconia based ceramic material having improved and well- balanced mechanical strength and toughness consists essentially of 0.5 to 50 vol % of Al.sub.2 O.sub.3 having an average grain size of 2 &mgr;m or less and the balance of a partially stabilized zirconia having an average grain size of 5 &mgr;m or less. The partially stabilized zirconia consists essentially of 8 to 12 mol % of CeO.sub.2, 0.05 to 4 mol % of TiO.sub.2 and the balance of ZrO.sub.2. Fine Al.sub.2 O.sub.3 grains having an average grain size of 1 &mgr;m or less are dispersed within the grains of the partially stabilized zirconia at a dispersion ratio. The dispersion ratio is defined as a ratio of the number of Al.sub.2 O.sub.3 grains dispersed within the grains of the partially stabilized zirconia relative to the number of the entire Al.sub.2 O.sub.3 grains dispersed in the ceramic material, and at least 2% in the present invention. The ceramic material can be made by the following process. A first constituent formed of the partially stabilized zirconia is mixed with a second constituent formed of Al.sub.2 O.sub.3 to obtain a mixture. The mixture is molded into a desired shape, and then sintered in the air under an atmospheric pressure to obtain the ceramic material.